An exclamation mark on the end of a title is a worrying sign. Lionel Bart doubled the pain with two, for his 1965 Robin Hood stage musical Twang!! (The critical consensus in favour of Baz Luhrmann's 2001 film Moulin Rouge! has incidentally meant that movie writers tend tactfully to remove Luhrmann's original exclamation mark.) Steven Soderbergh's The Informant! is a strained comedy that needn't have been either of those things. It is based on the true story of a 1990s corporate whistleblower called Mark Whitacre, played by Matt Damon - an excitable, Walter-Mitty-ish fellow who secretly informed the FBI of a price-fixing scam at his bio-tech firm, but himself became investigated for embezzlement. Does that sound dull? Just in case it does, Soderbergh has commissioned a relentlessly jazzy, wacky musical score from Hollywood veteran Marvin Hamlisch just so that we realise it's all supposed to be funny. Oddly, Whitacre's nerdy self-delusion and his stolid midwestern complacency make him sound like a character from an Alexander Payne movie, and I wondered how Payne would have directed The Informant! - much straighter, I suspect, allowing this strange and interesting story to speak for itself.